“Everyone is happy to do Snow Angels, but not as much about doing jumping jacks, when they’re virtually the same thing.” ~ Tim H. NPTI Instructor
A joint is where 2 bones meet. Flexibility is determined by a joint’s range of motion. During muscle flexion, the angle of the joint decreases as demonstrated in a bend or curling motion. During extension of a muscle, the angle of the joint is increased as demonstrated during a sitting to standing motion.
You may have also heard of abduction and adduction. An abduction movement is considered to be a movement away from the body’s midline or center (raising your arm to the side and up to your shoulder height). An adduction movement is a movement toward the midline of the body (clicking your heals together). There is also horizontal abduction and adduction. This is simply the same movement within the transverse plane, perpendicular to those just described. Horizontal movements are demonstrated when we do a chest press, push up, chest fly, or while we are hugging a tree (parallel to the horizon).
An isolation exercise is classified as a movement using only one joint. A compound exercise is classified as movements utilizing more than one joint.
chest press: (compound) horizontal shoulder adduction in the transverse plane, elbow extension
leg press: (compound) hip and knee extension
V-grip cable row: (compound) shoulder extension, elbow flexion
triceps pushdown: (isolation) elbow extension
biceps curl: (isolation) elbow flexion
dip: (compound) shoulder flexion, elbow extension